1. Field of the Invention
The present invention relates to IC tags (RFID tags) used for management of various types of information data on live stocks such as cows, pigs, and domestic fowls; pet animals such as dogs, cats, and birds; machines such as pachinko machines and copying machines; and other products and articles.
2. Description of the Related Art
Recently, IC tags (RFID (Radio Frequency Identification) tags) are widely used for management of various types of information data on live stocks such as cows, pigs, and domestic fowls; pet animals such as dogs, cats, and birds; machines such as pachinko machines and copying machines; and other products and articles, and the IC tag generally includes a micro IC (Integrated Circuit) chip and an antenna for radio communication, which are integrated with each other and covered with cladding material.
For instance, in a live stock management system using IC tags, an IC tag is attached to a proper potion of a body of each live stock, and information data such as a birth date, a body weight, information on foods given to the animal, and information on medical history are recorded in the IC tag, so that each animal can be managed from its birth date, during breeding, and until butchering by reading the recorded data with a reader/writer according to the necessity.
In the conventional technology, for enabling easy treatment and also for preventing damages caused by an external force loaded thereto, an antenna 54 having a metal-film pattern made of a conductive metal such as copper, aluminum or the like is formed on a synthetic resin sheet 53 as shown in FIG. 8C, and then an IC chip 55 is connected to and integrated with this antenna 54 for configuring a film-like IC chip-mounted body 52. Then, the IC chip-mounted body 52 is covered with synthetic resin cladding members 56, 57, as shown in FIG. 8B, to form an IC tag 51 as shown in FIG. 9 (Refer to, for instance, Patent document 1).
Furthermore, a synthetic resin-based filler 58 is used for coupling the synthetic resin cladding members 56, 57 and also for securing the IC chip-mounted body 52 to the synthetic resin cladding members 56, 57 tightly.
When the IC tags 51 as described above are used, for instance, in a live stock management system for pigs, the IC tag 51 is attached to a ear or other proper portion of a body of each pig for management of the anal.
Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-7991
However, as the conventional type of IC tags 51 are coated with synthetic resin cladding members 56, 57, the mechanical strength is relatively low, and when a pig bites the IC tag, the IC tag is easily broken, which disadvantageously makes it impossible to manage the animal. Furthermore, when the pig eats pieces of the broken IC tag, the broken pieces reside in the meat, which may cause a hazard for human health.
In addition, after the animal is sacrificed to obtain the meat, it is necessary to delete the recorded information data from the IC tag 51 and abort the tag, and a substantially long period of time is required for deleting the recorded data from a large number of IC tags. In addition, the IC tag 51 includes an IC chip 55, an antenna 54 made of copper or aluminum, cladding members 56, 57 made of synthetic resin, and synthetic resin-based filler 58, and abortion of a large number of IC tag 51 including organic materials is not desirable for protection of environment, and there is the strong need for solving this problem.
Reuse of the IC tag 51 is conceivable, but bacteria easily grow proliferously in the synthetic resin cladding members 56, 57, which sometimes causes diseases in pigs and is not desirable also from the viewpoint of sanitary. Even if the IC tags 51 are sterilized by boiling or with a chemical agent, the synthetic resin cladding members 56, 57 are low in the heat resistance and in the chemical resistance, so that reuse of the IC tags is difficult.
Further, about five years are required for growing cows, while life of IC tags 51 coated with the synthetic resin cladding members 56 57 is shorter than five years and comes to the end before the cows are sacrificed for meat processing, so that the durability is limited, which also makes reuse of the IC tags difficult.
Possibility of use of metal for cladding members was studied, because the mechanical strength of metal is high, but when a conductive member is present near the IC chip-mounted body 52, electric waves used for supplying electric power to the IC tag and used for transmitting and receiving data are disturbed or shielded, so that functions of the IC tags are lost. To prevent this problem, generally the IC tag is installed at a position far from a conductive member.
When IC tags are stored, transported, or used, the IC tags are often covered with a vessel or the like for protection from a stress or a shock loaded to the IC tags from the outside, but a conductive material causing a communication barrier can not be used as a material for the vessel when communication between the IC tag and a reader/writer terminal placed outside the vessel is required, and generally the IC tag is placed within a vessel made of a nonconductive material such as plastics.
For the reasons as described above, the conventional type of IC tags 51 can hardly be reused and are aborted, so that a huge amount of cost is required for a live stock management system using the IC tags 51.
In addition, the conventional type of IC tags 51 has low mechanical strength and are weak against such temperature conditions as high temperature or low temperature, and when humidity is high, the IC chip 55 is degraded due to moisture, which disables use of the IC chips 55 in many applications.